/*
** Nofrendo (c) 1998-2000 Matthew Conte (matt@conte.com)
**
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of version 2 of the GNU Library General
** Public License as published by the Free Software Foundation.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
** Library General Public License for more details.  To obtain a
** copy of the GNU Library General Public License, write to the Free
** Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
**
** Any permitted reproduction of these routines, in whole or in part,
** must bear this legend.
**
**
** map85.c
**
** mapper 85 interface
** $Id: map085.c,v 1.3 2001/05/06 01:42:03 neil Exp $
*/

#include <noftypes.h>
#include <nes_mmc.h>
#include <nes.h>
#include <log.h>

static struct
{
    int counter, latch;
    int wait_state;
    bool enabled;
} irq;

/* mapper 85: Konami VRC7 */
static void map85_write(uint32 address, uint8 value)
{
    uint8 bank = address >> 12;
    uint8 reg = (address & 0x10) | ((address & 0x08) << 1);

    switch (bank)
    {
    case 0x08:
        if (0x10 == reg)
            mmc_bankrom(8, 0xA000, value);
        else
            mmc_bankrom(8, 0x8000, value);
        break;

    case 0x09:
        /* 0x10 & 0x30 should be trapped by sound emulation */
        mmc_bankrom(8, 0xC000, value);
        break;

    case 0x0A:
        if (0x10 == reg)
            mmc_bankvrom(1, 0x0400, value);
        else
            mmc_bankvrom(1, 0x0000, value);
        break;

    case 0x0B:
        if (0x10 == reg)
            mmc_bankvrom(1, 0x0C00, value);
        else
            mmc_bankvrom(1, 0x0800, value);
        break;

    case 0x0C:
        if (0x10 == reg)
            mmc_bankvrom(1, 0x1400, value);
        else
            mmc_bankvrom(1, 0x1000, value);
        break;

    case 0x0D:
        if (0x10 == reg)
            mmc_bankvrom(1, 0x1C00, value);
        else
            mmc_bankvrom(1, 0x1800, value);
        break;

    case 0x0E:
        if (0x10 == reg)
        {
            irq.latch = value;
        }
        else
        {
            switch (value & 3)
            {
            case 0:
                ppu_mirror(0, 1, 0, 1); /* vertical */
                break;

            case 1:
                ppu_mirror(0, 0, 1, 1); /* horizontal */
                break;

            case 2:
                ppu_mirror(0, 0, 0, 0);
                break;

            case 3:
                ppu_mirror(1, 1, 1, 1);
                break;
            }
        }
        break;

    case 0x0F:
        if (0x10 == reg)
        {
            irq.enabled = irq.wait_state;
        }
        else
        {
            irq.wait_state = value & 0x01;
            irq.enabled = (value & 0x02) ? true : false;
            if (true == irq.enabled)
                irq.counter = irq.latch;
        }
        break;

    default:
#ifdef NOFRENDO_DEBUG
        log_printf("unhandled vrc7 write: $%02X to $%04X\n", value, address);
#endif /* NOFRENDO_DEBUG */
        break;
    }
}

static void map85_hblank(int vblank)
{
    UNUSED(vblank);

    if (irq.enabled)
    {
        if (++irq.counter > 0xFF)
        {
            irq.counter = irq.latch;
            nes_irq();

            // return;
        }
        // irq.counter++;
    }
}

static map_memwrite map85_memwrite[] = {{0x8000, 0xFFFF, map85_write}, {-1, -1, NULL}};

static void map85_init(void)
{
    mmc_bankrom(16, 0x8000, 0);
    mmc_bankrom(16, 0xC000, MMC_LASTBANK);

    mmc_bankvrom(8, 0x0000, 0);

    irq.counter = irq.latch = 0;
    irq.wait_state = 0;
    irq.enabled = false;
}

mapintf_t map85_intf = {85,             /* mapper number */
                        "Konami VRC7",  /* mapper name */
                        map85_init,     /* init routine */
                        NULL,           /* vblank callback */
                        map85_hblank,   /* hblank callback */
                        NULL,           /* get state (snss) */
                        NULL,           /* set state (snss) */
                        NULL,           /* memory read structure */
                        map85_memwrite, /* memory write structure */
                        NULL};

/*
** $Log: map085.c,v $
** Revision 1.3  2001/05/06 01:42:03  neil
** boooo
**
** Revision 1.2  2001/04/27 14:37:11  neil
** wheeee
**
** Revision 1.1  2001/04/27 12:54:40  neil
** blah
**
** Revision 1.1.1.1  2001/04/27 07:03:54  neil
** initial
**
** Revision 1.1  2000/10/24 12:19:33  matt
** changed directory structure
**
** Revision 1.10  2000/10/22 19:17:46  matt
** mapper cleanups galore
**
** Revision 1.9  2000/10/22 15:03:14  matt
** simplified mirroring
**
** Revision 1.8  2000/10/21 19:33:38  matt
** many more cleanups
**
** Revision 1.7  2000/10/10 13:58:17  matt
** stroustrup squeezing his way in the door
**
** Revision 1.6  2000/08/16 02:50:11  matt
** random mapper cleanups
**
** Revision 1.5  2000/07/23 14:37:21  matt
** added a break statement
**
** Revision 1.4  2000/07/15 23:52:19  matt
** rounded out a bunch more mapper interfaces
**
** Revision 1.3  2000/07/10 13:51:25  matt
** using generic nes_irq() routine now
**
** Revision 1.2  2000/07/10 05:29:03  matt
** cleaned up some mirroring issues
**
** Revision 1.1  2000/07/06 02:47:47  matt
** initial revision
**
*/
